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    <title>Document</title>
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  <body>
    <script>
      const user = {
        name: "jack",
        jump() {
          console.log("jump");
        },
      };
      function say() {
        console.log("hello");
      }
      user.sayHello = say;
      user.add = function (x, y) {
        return x + y;
      };
      console.log(user.add(1, 2));
    </script>
  </body>
</html>
